Connection structure

ABSTRACT

A method for manufacturing connection structure, the method includes arranging conductive particles and a first composite on a first electrode located on a first surface of a first member, arranging a second composite on a region other than the first electrode of the first surface, arranging the first surface and a second surface of a second member where a second electrode is located, so that the first electrode and the second electrode are opposed to each other, pressing the first member and the second member; and curing the first composite and the second composite.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional of U.S. patent application Ser. No. 16/004,281filed on Jun. 8, 2018, which claims the benefit of priority from theprior Japanese Patent Application No. 2018-015665, filed on Jan. 31,2018, the entire contents of which are incorporated herein by reference.

FIELD

An embodiment of the present invention relates to a connection structurehaving a connection configuration of electrodes made of conductivecomposite and a method for manufacturing the connection structure.

BACKGROUND

In general, an anisotropic conductive films (ACF) containing conductiveparticles is widely used when an electronic component such as anintegrated circuit is mounted on a substrate in COG (Chip on Glass)connection for connecting an integrated circuit directly to a glasssubstrate such as a liquid-crystal display or FOG (Film on Glass)connection for connecting a flexible printed board to a glass substrateof a flat panel display. The anisotropic conductive film is athermosetting resin film with fine conductive particles dispersedtherein. By interposing the anisotropic conductive film between alignedelectrodes and performing thermal compression, the conductive particlespositioned between the electrodes can form a conductive route. On theother hand, insulation properties of the thermosetting resin can reducea short circuit between electrodes adjacent in a substrate surfacedirection. That is, the anisotropic conductive film has anisotropy offorming conductivity in a pressurizing direction (direction of both ofthe electrodes) and insulation properties are kept in a non-pressurizingdirection (surface direction of the substrate). Having thesecharacteristic, the anisotropic conductive film can collectively connecta plurality of electrodes provided on an integrated circuit, printedboard, glass substrate, or the like, and can retain insulationproperties of adjacent electrodes in the substrate surface direction.

However, with high fineness and high density of connection circuits inelectronic devices in recent years, reliability of connection using theanisotropic conductive film matters. That is, when the size of anelectrode as a connection target decreases, the number of conductiveparticles contributing to conductivity between paired electrodesdecreases, and connection reliability between the electrodes may not besufficiently obtained. Moreover, when a space between electrodesadjacent in the substrate surface direction is narrowed, both of theadjacent electrodes and the conductive particles may be in contact witheach other, and insulation reliability may not be sufficiently obtained.Thus, for example, an anisotropic conductive film in a state withconductive particles dispersed by means such as application of amagnetic field and as being separated from other conductive particles isdisclosed (for example, refer to Japanese Unexamined Patent ApplicationPublication No. 2015-167106).

SUMMARY

A method for manufacturing connection structure according to anembodiment of the present invention, the method includes arrangingconductive particles and a first composite on a first electrode locatedon a first surface of a first member, arranging a second composite on aregion other than the first electrode of the first surface, arrangingthe first surface and a second surface of a second member where a secondelectrode is located, so that the first electrode and the secondelectrode are opposed to each other, pressing the first member and thesecond member, and curing the first composite and the second composite.

A connection structure according to an embodiment of the presentinvention includes a first member having a first surface, a firstelectrode located on the first surface, a second member having a secondsurface opposed to the first surface, a second electrode opposed to thefirst electrode and located on the second surface, a first resin andconductive particles arranged between the first electrode and the secondelectrode, and a second resin arranged between the first electrode andthe second electrode and between a region other than the first electrodeon the first surface and a region other than the second electrode on thesecond surface. The first resin is in contact with the first electrode,the second resin is in contact with the second electrode. The firstresin and the second resin are different compositions from each other.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A to FIG. 1E shows a configuration of a connection structureaccording to an embodiment of the present invention;

FIG. 2A to FIG. 2C shows a method for producing the connection structureaccording to an embodiment of the present invention;

FIG. 3A to FIG. 3C shows a method for producing the connection structureaccording to an embodiment of the present invention;

FIG. 4A to FIG. 4C shows a method for producing the connection structureaccording to an embodiment of the present invention;

FIG. 5A to FIG. 5E shows a method for producing the connection structureaccording to an embodiment of the present invention;

FIG. 6A to FIG. 6F shows a method for producing the connection structureaccording to an embodiment of the present invention;

FIG. 7A to FIG. 7F shows a method for producing the connection structureaccording to an embodiment of the present invention;

FIG. 8A to FIG. 8F shows a method for producing the connection structureaccording to an embodiment of the present invention;

FIG. 9A to FIG. 9C shows a configuration of a connection structureaccording to an embodiment of the present invention;

FIG. 10A to FIG. 10C shows a configuration of a connection structureaccording to an embodiment of the present invention;

FIG. 11A and FIG. 11B shows an example of the connection structureaccording to an embodiment of the present invention;

FIG. 12A and FIG. 12B shows an example of the connection structureaccording to an embodiment of the present invention;

FIG. 13A and FIG. 13B shows an example of the connection structureaccording to an embodiment of the present invention;

FIG. 14A and FIG. 14B shows an example of the connection structureaccording to an embodiment of the present invention;

FIG. 15A and FIG. 15B shows an example of the connection structureaccording to an embodiment of the present invention; and

FIG. 16A and FIG. 16B shows an example of the connection structureaccording to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the drawings and the like. The present invention may becarried out in various embodiments, and should not be construed as beinglimited to any of the following embodiments. In the drawings, componentsmay be shown schematically regarding the width, thickness, shape and thelike, instead of being shown in accordance with the actual sizes, forthe sake of clear illustration. The drawings are merely examples and donot limit the present invention in any way. In the specification and thedrawings, components that are substantially the same as those describedor shown previously bear the identical reference signs thereto (or theidentical reference signs followed by letters “a”, “b” or the like), anddetailed descriptions thereof may be omitted. The terms “first”,“second” and the like used for elements are merely provided fordistinguishing the elements and do not have any other significanceunless otherwise specified.

In the specification and the claims, an expression that a component is“on” the other component encompasses a case where such a component is incontact with the other component and also a case where such a componentis above or below the other component, namely, a case where stillanother component is provided between such a component and the othercomponent, unless otherwise specified.

In the anisotropic conductive film, since the sequence of the conductiveparticles is irregularly disturbed when substrates are subjected tothermal compression. Thus, it is difficult to sufficiently solveproblems such as conduction failure due to the absence of conductiveparticles between the electrodes and a short circuit due to a contact ofthe conductive particles between the adjacent electrodes. Moreover, witha heat curing connection scheme, a dimensional change occurs inprinciple, due to a difference in coefficient of thermal expansionbetween upper and lower substrates, and a problem of deviation occursbetween the electrodes formed on the upper and lower substrates. Inseveral embodiments described further below, one aspect of a connectionstructure capable of solving one or plurality of these problems isdescribed.

In the specification, a connection structure in COG connection forconnecting an integrated circuit (second electronic component) to aglass substrate of a liquid-crystal display (a first electroniccomponent) is described by way of example. However, the connectionstructure is not limited to this, and may be a connection structure inFOG connection for connecting a flexible printed board to a glasssubstrate of a flat panel display. In this case, the second electroniccomponent may be a flexible printed board such as a TAB (Tape AutomatedBonding) or COF (Chip on film).

First Embodiment Configuration of Connection Structure

FIG. 1A to FIG. 1C shows the configuration of a connection structureaccording to one embodiment of the present invention. FIG. 1A is a planview of the connection structure according to one embodiment of thepresent invention. FIG. 1B is a sectional view along an A-A′ line ofFIG. 1A. FIG. 1C is an enlarged sectional view of a conductive particlein a region B of FIG. 1B.

As shown in FIG. 1A and FIG. 1B, a first electronic component 101includes a terminal 104, a first insulating film 106, a secondinsulating film 108, and a first electrode 110 on a connection surface(first surface) of a first member 102. On the connection surface (firstsurface) of the first electronic component 101, a second electroniccomponent 111 is mounted. The second electronic component 111 includes asecond electrode 114 on a connection surface (second surface) of asecond member 112. The first surface of the first electronic component101 and the second surface of the second electronic component 111 arearranged so as to be opposed to each other. The connection structure 100serves a function of physical connection between the first electroniccomponent 101 and the second electronic component 111 and electricalconnection between the first electrode 110 and the second electrode 114.The connection structure 100 includes the first member 102 having thefirst surface, the first electrode 110, the second member 112 having thesecond surface, the second electrode 114, conductive particles 10, afirst resin 20, and a second resin 30.

A plurality of first electrodes 110 are arranged on the first surface ofthe first member 102. On the first surface of the first member 102, asecond insulating film 108 is arranged in a region other than a regionwhere the first electrodes 110 are arranged. A plurality of secondelectrodes 114 are arranged on the second surface of the second member112 so as to correspond to the plurality of first electrodes 110. On thesecond surface of the second member 112, an insulating film may bearranged in a region other than a region where the second electrodes 114are arranged.

The plurality of first electrodes 110 and the plurality of secondelectrodes 114 are arranged so as to be the first electrode 110 and thesecond electrode 114 are opposed to each other. The plurality ofconductive particles 10 and the first resin 20 are arranged between theopposing first electrode 110 and second electrode 114. The plurality ofconductive particles 10 are arranged in a surface direction (D2-D3surface direction) between the opposing first electrode 110 and secondelectrode 114. One conductive particle 10 is arranged between theopposing first electrode 110 and second electrode 114 in an opposingdirection (D1 direction) of the first electrode 110 and the secondelectrode 114. Each of the plurality of conductive particles 10 are incontact with the opposing first electrode 110 and second electrode 114.As shown in FIG. 1C, the conductive particle 10 is pressured anddeformed in the opposing direction (D1 direction) between the firstelectrode 110 and the second electrode 114 by a method for manufacturingconnection structure, which will be described further below. That is, adistance between the first electrode 110 and the second electrode 114 inthe opposing direction (D1 direction) of the electrodes is substantiallyequal to the height of the conductive particle 10 in the opposingdirection (D1 direction) of the electrodes. The height of the conductiveparticle 10 in the opposing direction (D1 direction) of the electrodesis pressured and deformed by approximately 10% to 40%. With a stressprovided among the first electrode 110, the conductive particles 10, andthe second electrode 114, the first resin 20 is eliminated at thecontact part between the first electrode 110 and the conductive particle10 and the contact part between the second electrode 114 and theconductive particle 10. Furthermore, even if a natural oxide film isformed on the first electrode 110, the conductive particle 10, or thesecond electrode 114 and its surface is insulated, the first electrode110 and the second electrode 114 are pressure-welded with the conductiveparticle 10 interposed therebetween, thereby breaking the natural oxidefilm to form a conductive route. Furthermore, deformation of theconductive particle 10 can increase the area of contact between thefirst electrode 110 and the conductive particle 10 and the area ofcontact between the second electrode 114 and the conductive particle 10.This arrangement allows the conductive particle 10 to electricallyconnect the first electrode 110 and the second electrode 114.

The plurality of conductive particles 10 are dispersed in the firstresin 20 between the first electrode 110 and the second electrode 114.Each of the plurality of conductive particles 10 are surrounded by thefirst resin 20 between the first electrode 110 and the second electrode114 in the surface direction (D2-D3 surface direction). The first resin20 is an insulating resin. Thus, the connection structure 100 hasinsulation properties in the surface direction (D2-D3 surfacedirection). However, the plurality of conductive particles 10 arrangedbetween the opposing first electrode 110 and second electrode 114 andadjacent to each other in the surface direction (D2-D3 surfacedirection) may be in contact with each other. When the conductiveparticles 10 adjacent to each other in the surface direction (D2-D3surface direction) are in contact with each other, the conductiveparticles 10 adjacent to each other are also electrically connected.This arrangement allows the conductive particles 10 to further reliablyconnect the opposing first electrode 110 and second electrode 114electrically. The distance between the adjacent conductive particles 10can be appropriately controlled according to the concentration of theconductive particles 10 mixed into a first composite 20′, which will bedescribed further below.

As shown in FIG. 1A and FIG. 1B, the plurality of conductive particles10 and the first resin 20 are arranged on an upper surface of the firstelectrode 110 (or a lower surface of the second electrode 114). Theplurality of conductive particles 10 and the first resin 20 are arrangedin each certain region when viewed in the opposing direction (D1direction) of the electrodes. In the present embodiment, the diameter ofthe conductive particle 10 when viewed in the opposing direction (D1direction) of the electrodes is in a range between a value equal to orlarger than 2 μm and a value equal to or smaller than 10 μm. The numberof regions where the electrode particles 10 and the first resin 20 arearranged on the upper surface of one first electrode 110 (or the lowersurface of one second electrode 114) is one or more, and the regions arepreferably separated from each other by 5 μm or more. The number ofconductive particles 10 in one region where the conductive particles 10and the first resin 20 are arranged is preferably equal to or largerthan one and equal to or smaller than seven. The number of conductiveparticles 10 arranged in one region is preferably seven, and morepreferably three. When viewed in the opposing direction (D1 direction)of the electrodes, the number of conductive particles 10 arrangedbetween the opposing first electrode 110 and second electrode 114 ispreferably in a range between a value equal to or larger than seven per400 μm² and a value equal to or smaller than twenty per 400 μm². Whenthe number of conductive particles 10 is smaller than seven per 400 μm²,the connection resistance value may tend to vary. When the number ofconductive particles 10 is larger than twenty per 400 μm², the pressuredeformation amount of the conductive particles 10 may be decreased dueto load dispersion, causing the natural oxide film to be unable to bebroken at a connection region and increasing connection resistance.Furthermore, when the number of conductive particles 10 is larger thantwenty per 400 μm², the pressure deformation amount tends to change withtime, and connection resistance tends to change with time. Theabove-described arrangement allows the conductive particles 10 toreliably connect the opposing first electrode 110 and second electrode114, and can prevent a short circuit between the plurality of firstelectrodes 110 adjacent to each other in the surface direction (D2-D3surface direction), between the plurality of second electrodes 114adjacent to each other in the surface direction (D2-D3 surfacedirection), and between the first electrode 110 and the second electrode114 not opposed to each other.

In the present embodiment, the shape of the region where the conductiveparticles 10 and the first resin 20 are arranged when viewed in theopposing direction (D1 direction) of the electrodes is a circle.However, the shape is not limited to this, and the region where theconductive particles 10 and the first resin 20 are arranged may have anyshape satisfying the above-described condition. In the presentembodiment, the region where the conductive particles 10 and the firstresin 20 are arranged is positioned at two locations on the uppersurface of one first electrode 110 (or the lower surface of one secondelectrode 114). Also, seven conductive particles 10 are arranged in oneregion. However, this is not meant to be restrictive, and the number ofregions where the conductive particles 10 and the first resin 20 arearranged on the upper surface of one first electrode 110 (or the lowersurface of one second electrode 114) can be adjusted as appropriate tosatisfy the above-described condition, depending on the area of theupper surface of the first electrode 110 (or the lower surface of thesecond electrode 114), the area of the region where the conductiveparticles 10 and the first resin 20 are arranged, and the size of theconductive particles 10. Also, the number of conductive particles 10arranged in one region can be adjusted as appropriate to satisfy theabove-described condition, depending on the size of the conductiveparticles 10 and concentration of the conductive particles 10 mixed intothe first composite 20′.

The second resin 30 is further arranged between the first surface of thefirst member 102 and the second surface of the second member 112. Thesecond resin 30 is arranged in a region not between the opposing firstelectrode 110 and second electrode 114. The second resin 30 is arrangedbetween a region other than the first electrode of the first surface anda region other than the second electrode of the second surface. That is,the second resin 30 is arranged between the plurality of firstelectrodes 110 adjacent to each other in the surface direction (D2-D3surface direction) and on the periphery thereof (between the pluralityof second electrodes 114 adjacent to each other in the surface direction(D2-D3 surface direction) and on the periphery thereof). Furthermore,the second resin 30 is also arranged between the first electrode 110 andthe second electrode 114 and in a region other than the region where theconductive particles 10 and the first resin 20 are arranged. The secondresin 30 is arranged between the regions adjacent in the surfacedirection (D2-D3 surface direction) where the plurality of conductiveparticles 10 and the first resin 20 are arranged and on the peripherythereof. The second resin 30 is arranged between the regions where theplurality of conductive particles 10 and the first resin 20 adjacent inthe surface direction (D2-D3 surface direction) are arranged and on theperiphery thereof. In other words, the conductive particles 10 and thefirst resin 20 are surrounded by the second resin 30 in the surfacedirection (D2-D3 surface direction). That is, when viewed in theopposing direction (D1 direction) of the electrodes, the plurality ofconductive particles 10 are surrounded by the first resin 20, and thefirst resin 20 is surrounded by the second resin 30. The second resin 30is an insulating resin. Thus, the connection structure 100 hasinsulation properties in the surface direction (D2-D3 surfacedirection). This arrangement allows the second resin 30 to reliablyinsulate between the plurality of first electrodes 110 adjacent in thesurface direction (D2-D3 surface direction), between the plurality ofsecond electrodes 114 adjacent in the surface direction (D2-D3 surfacedirection), and between the first electrode 110 and the second electrode114 not opposed to each other.

The boundary between the first resin 20 and the second resin 30 can beobserved by cross-sectional observation of the connection structure 100.From a difference in composition between the first resin 20 and thesecond resin 30, the boundary between the first resin 20 and the secondresin 30 can also be determined by a process/observation apparatus suchas a Focused Ion Beam (FIB) process observation apparatus, a ScanningElectron Microscope (SEM), or a Transmission Electron Microscope (TEM).

If the first composite 20′ and a second composite 30′, which will bedescribed further below, are less phase-soluble, the boundary betweenthe first resin 20 and the second resin 30 can be observed as aninterface. If the first composite 20′ and a second composite 30′ aresimilar to each other in composition and the interface therebetweendisappear in a process described further below, the boundary may beobserved as a boundary layer with the first resin 20 and the secondresin 30 mixed together.

The first electronic component 101 may be, for example, a flat displaysuch as a liquid-crystal display, an organic EL display, or a plasmadisplay, and the first member 102 is preferably an insulating substratesuch as, for example, a glass substrate or a transparent film substrate.The first electrode 110 corresponds to, for example, an externalconnection terminal provided to a display. The first electrode 110 andthe terminal 104 may be formed of a transparent conductive material suchas ITO (indium tin oxide) or IZO (indium zinc oxide); a metal such ascopper (Cu), aluminum (Al), molybdenum (Mo), or titanium (Ti); an alloyincluding at least one type thereof (such as Mo—Ti alloy); or alaminated structure of these materials (such as Mo/Cu laminatedstructure, Mo—Ti alloy/Cu laminated structure, Mo/Al laminatedstructure, Mo/Al/Mo laminated structure, or Al/Ti laminated structure).

The second electronic component 111 may be a Si chip having anintegrated circuit formed thereon. In this case, the second electrode114 corresponds to an external connection terminal (bonding pad)provided to the integrated circuit. The second member 112 is preferablya silicon substrate, a SiC substrate, a sapphire substrate, a plasticsubstrate, or the like. The second electrode 114 is preferably formed,for example, of gold (Au) or by plating a surface of copper (Cu) withgold. When the second electronic component 111 is, for example, aflexible printed board, the second member 112 is preferably, forexample, an insulating polymer film made of a polyimide, a para-basedpolyamide, or the like. The second electrode 114 corresponds to anexternal connection terminal provided to, for example, the flexibleprinted board, is generally formed of copper (Cu), and has its surfaceplated with gold.

The size of each of the first electrode 110 and the second electrode 114when viewed in the opposing direction (D1 direction) is not limited toparticular sizes. The distance between the pluralities of firstelectrodes 110 adjacent in the surface direction (D2-D3 surfacedirection) (the distance between the pluralities of second electrodes114 adjacent in the surface direction) is not limited to particularvalues, and is, for example, at least equal to or large than 5 μm. Thisconfiguration allows the first electrode 110 and the second electrode114 to be electrically connected without impairing insulationproperties. In the present embodiment, the first electrode 110 and thesecond electrode 114 are arranged so that short sides thereof arealigned in a line at one end part of each of the first electroniccomponent 101 and the second electronic component 111. However, this isnot meant to be restrictive, and a plurality of rows of the firstelectrodes 110 and the second electrodes 114 may be arranged, and thefirst electrodes 110 and the second electrodes 114 may be arranged in astaggered formation.

The conductive particle 10 included in the connection structure 100 maybe in an oblate spheroidal shape. The diameter (longitudinal diameter)of the conductive particle 10 when viewed in the opposing direction (D1direction) of the electrodes is in a range between a value equal to orlarger than 2 μm and a value equal to or smaller than 10 μm. Theconductive particle 10 may originally have a spherical shape with theabove-described longitudinal diameter as a diameter, and may be deformedto be flat in the opposing direction (D1 direction) of the electrodes bya range between a value equal to or larger than 10% and a value equal toor smaller than 40% with respect to 100% of the longitudinal diameter.The diameter (longitudinal diameter) and the pressure deformation amountof the conductive particle 10 can be selected as appropriate from thevalues in the above-described range, depending on the type of the firstelectronic component 101 and the second electronic component 111, themethod for manufacturing each connection structure, and so forth. Whilethe conductive particle 10 has a round shape in the present embodimentas shown in FIG. 1D, this is not meant to be restrictive and, forexample, as shown in FIG. 1E, the conductive particle 10 may have aspherical shape with a plurality of protrusions on its surface (aconfeito shape). This is more preferable because, with the surface ofthe spherical shape having a fine convex configuration, the naturaloxide film in the connection region can be broken, for example.

The material of the conductive particle 10 is not limited to particularmaterials, and any can be selected as appropriate for use from knownconductive particles. The conductive particle 10 may be a metal-coatedparticle by coating with metals 10 b and 10 c such as nickel (Ni),copper (Cu) or gold (Au), a particle core with a highly-hard resinmaterial coated with a rubber-like elastic resin or a particle core 10 awith a highly-hard inorganic material coated with a rubber-likeinorganic elastic body, as shown in FIG. 1D and FIG. 1E. In metalcoating, a Ni/Cu laminated structure, a Ni/Au laminated structure, or aCu/Au laminated structure may be formed by, for example, barrelsputtering, metal nanoparticle plating, electroless plating, ultrasonicplating, or the like.

The first resin 20 and the second resin 30 are formed by curing thefirst composite 20′ and the second composite 30′ including differentmaterials. The materials of the first composite 20′ and the secondcomposite 30′ are not limited to particular materials, and any can beselected as appropriate from known curable resin materials. In thepresent embodiment, the curable resin materials of the first composite20′ and the second composite 30′ both contain a radical-polymerizationresin. As the radical-polymerization resin, a (meth)acrylic monomer or(meth)acrylate oligomer is preferable, and one bonded in an ester formis more preferable. The (meth)acrylate oligomer has at least one(meth)acryloyl group or more and, for example, epoxy acrylate, urethaneacrylate, polyester acrylate, polybutadiene acrylate, polyol acrylate,polyether acrylate, silicone resin acrylate, melamine acrylate, or thelike can be used. The (meth)acryl oligomer may be monofunctional orpolyfunctional, and preferably contains a polyfunctional monomer oroligomer. The curably resin material may be configured by selecting twoor more types from (meth)acrylate monomers and (meth)acrylate oligomers.

In particular, as a curable resin material of the second composite 30′,one with a low volume shrinkage ratio at the time of curing ispreferable. Thus, the (meth)acrylic monomer may contain, for example, anamide methylol structure portion, and may contain a dendrimer or hyperbranch polymer structure portion. In a (meth)acrylic monomer compoundhaving an amide methylol structure portion, together with polymerizationof carbon-carbon double bonds derived from (meth)acrylic acid,methylene-oxygen bonds in the amide methylol structure portion arecleaved at the time of photocuring. Thus, with the second compound 30′containing a (meth)acrylic monomer compound having at least one amidemethylol structure portion formed of —CO'NH—CH₂—O— in a molecule as acurable component, the volume shrinkage ratio of the second resin 30 dueto curing of the second composite 30′ can be more reduced, and warpagedue to a difference in flexural rigidity between the first electroniccomponent 101 and the second electronic component 111 can be reduced.With a branch including a dendrimer or hyperbranch polymer structureportion having an acryl group, a Van der Waals distance between branchesbecomes shorter than a Van der Waals distance between general molecules.Thus, with the second composite 30′ containing a dendrimer orhyperbranch polymer structure portion having an acryl group as a curablecomponent, the volume shrinkage ratio of the second resin 30 due tocuring of the second composite 30′ can be more reduced, and warpage dueto a difference in flexural rigidity between the first electroniccomponent 101 and the second electronic component 111 can be reduced.

As the curable resin material of the second composite 30′, afluorene-based acrylate is preferably used. The second composite 30′ maycontain an ene/thiol-based curable resin containing a composite havingan ethylene unsaturated double bond and a thiol compound as a curablecomponent, at least one of these components may contain a compoundhaving a 9,9-bisarylfluorene skeleton. The 9,9-bisarylfluorene compoundmay be a 9,9-bisarylfluorene compound having an ethylene unsaturatedbond and/or a 9,9-bisarylfluoren compound having a mercapto group. Asthe ethylene unsaturated compound, for example,9,9-bis(4-acryloyloxyethoxyphenyl)fluorene (produced by Osaka GasChemicals Co., Ltd., OGSOL EA-0200) and phenoxyethyl acrylate (producedby KYOEISHA CHEMICAL CO., LTD., LIGHT ACRYLATE POA) may be used. As thethiol compound, for example, pentaerythritol tetra (3-mercaptobutyrate)(produced by SHOWA DENKO K. K., Karenz MT PE1) may be used. With thesecond composite 30′ containing this curable resin material, the volumeshrinkage ratio of the second resin 30 due to curing of the secondcomposite 30′ can be more reduced, and warpage due to a difference inflexural rigidity between the first electronic component 101 and thesecond electronic component 111 can be reduced.

As the curable resin material of the second composite 30′, an enecompound having in a molecule two or more functional groups selectedfrom a group of an allyl ether group, a vinyl ether group, an acrylategroup, and a methacrylate group or ene compound as a mixture of two ormore types of the above-described ene compounds, and a substanceobtained by performing oxidizing-compound-process on the ene/thiol-basedcurable resin containing a thiol compound having two or more thiolgroups in one molecule may be used. A compound having two or moremercapto groups in one molecule may contain esters obtained frommercaptocarboxylic acid and polyhydric alcohol, aliphatic polythiols,aromatic polythiols, and other polythiols, or one, two or more of thesemay be used. The oxidizing-compound process is preferably performed witha gas having oxidative capacity. The gas having oxidative capacity is acompound having air properties and oxidative capacity under temperatureand atmospheric pressure conditions for performing oxidizing-compoundprocess. As the gas having oxidative capacity, air, oxygen, ozone, orthe like can be used, and a mixture gas partially containing any ofthese may be used. The second composite 30′ can enhance stability withtime by performing oxidizing-compound process on the above-describedphotocurable resin material.

The materials of the first composite 20′ and the second composite 30′further contain a photocuring initiating component. The photocuringinitiating component is a photoradical initiator, and may be anycompound which generates radicals by irradiating ultraviolet rays orvisible rays. As an ultraviolet-ray radical initiator, for example, anacetophenone-based initiator, a benzoin-ether-based initiator, abenzophenone-based initiator, an α-diketone-based initiator, athioxanthone-based initiator, or the like can be used. As a visible-rayradical initiator, for example, a camphorquinone-based compound, anacylphosphine oxide compound, or the like can be used. Also, oneclassified as an ultraviolet-ray radical initiator but capable ofvisible-ray radical initiation by using combination with a sensitizermay be used. The sensitizer can be appropriately used as required. Asthe sensitizer, a known composite can be used. For example, anamine-based compound, a (meth)acrylic acid ester of an alkanol amine, orthe like can be used. A plurality of types of the photocuring initiatingcomponent and the sensitizer can be used in combination. For example, byusing an ultraviolet-ray radical initiator and a visible-ray radicalinitiator in combination, a curable wavelength region can be expanded.The photocuring initiating component is more preferably a photoradicalinitiator which generates radicals with a irradiation light in a rangeof wavelength between a value equal to or larger than 300 nm and a valueequal to or smaller than 500 nm. The photocuring initiating component iscompounded in the curable resin material so that the curable resinmaterial can be curing at room temperatures with a light irradiation fora period of preferably equal to or shorter than approximately threeseconds, more preferably equal to or shorter than one second. Thecurable resin material is selected as appropriate so as to allow curingat room temperatures with the above-described time period.

In the present embodiment, the first composite 20′ and the secondcomposite 30′ more preferably further contain a shielding part curableactivation compound such as, for example, a chain transfer agent. Thechain transfer agent transmits radicals generated by light irradiationto a shielding part which light does not directly reach. As the chaintransfer agent, for example, a compound containing at least one or moreof selected from a urethane bond, a urea bond, and an isocyanate groupand one or more of alkoxysilyl group can be used. In photocuringreaction using the above-described chain transfer agent, polyalcoholhaving a hydroxyl group as one type of anion is generated as aby-product. With this polyalcohol and the alkoxysilyl group containingin the chain transfer agent undergoing a transesterification, curingfurther proceeds. That is, with the chain transfer agent being containedin the first composite 20′ and the second composite 30′, radical curingand anion curing occur simultaneously, thereby allowing curing of theshielding part where light does not directly reach.

With the first composite 20′ and the second composite 30′ containing ashielding part curable activation compound, the first composite 20′ andthe second composite 30′ can be reliably cured even under conditionswith the connection method, the material of the first electroniccomponent 101, the second electronic component 111, the first electrode110, and the second electrode 114, and so forth in which the firstcomposite 20′ and the second composite 30′ cannot be cured only with theaction of a photocuring initiating component by light irradiation.

In the present embodiment, the material of the first composite 20′ mayfurther contain an anaerobic curing initiating component. As theanaerobic curing initiating component, a known group including organicperoxide and a curing accelerator can be used. As the organic peroxide,for example, any of hydroperoxides, ketone peroxides, diallyl peroxides,peroxyesters, and so forth can be used. As the curing accelerator, forexample, an o-benzoic sulfimide (saccharin), a hydrazine compound, anamine compound, a mercaptan compound, or the like can be used. Aplurality of types of the anaerobic curing initiation component and thecuring accelerator may be used in combination.

In the present embodiment, the first composite 20′ is surrounded by thefirst surface (including the first electrode 110), the second surface(including the second electrode 114), and the second composite 30′.Furthermore, the first composite 20′ is in contact with the firstelectrode 110, the second electrode 114, and the conductive particles10. The first electrode 110, the second electrode 114, and theconductive particles 10 contain transition metals. Thus, with the firstcomposite 20′ containing an anaerobic curing initiating component, aredox reaction by the cure acceleration agent and the transition metalions dissolves peroxide, thereby allowing anaerobic curing of the firstcomposite 20′ to be initiated.

With the first composite 20′ further containing an anaerobic curinginitiating component, the first composite 20′ can be reliably cured evenunder conditions with the connection method, the material of the firstelectronic component 101, the second electronic component 111, the firstelectrode 110, and the second electrode 114, and so forth in which thefirst composite 20′ cannot be cured only with the action of aphotocuring initiating component by light irradiation.

The additive can be appropriately used as required to improve or modifythe properties such as fluidity, coating characteristics,preservability, curing characteristics, and physical properties aftercuring. As the additive, any known compound can be used. Examples of theadditive include a silane coupler, a diluent, a modifying agent, asurface active agent, a preservative stabilizer, an antiforming agent,and a leveling agent, although not limited thereto. The silane coupleris not limited to particular agent and for example, any of epoxy-based,amino-based, mercapto/sulfide-based, and ureido-based ones and so forthcan be used. With the addition of silane coupler, adhesion at theinterface between the organic material and the inorganic material isimproved.

The viscosity of the first composite 20′ is higher than the viscosity ofthe second composite 30′. The viscosity of the first composite 20′ is ina range between a value equal to or higher than 5×10³ cP and a valueequal to or lower than 5×10⁵ cP. The viscosity of the second composite30′ is in a range between a value equal to or higher than 2×10³ cP and avalue equal to or lower than 2×10⁵ cP. It is required that the viscosityof the first composite 20′ is twice as high as the viscosity of thesecond composite 30′ or higher. The viscosity of the first composite 20′and the second composite 30′ can be controlled also by the degree ofpolymerization of the resin material contained in the first composite20′ and the second composite 30′. The viscosity of each composite can beselected as appropriate from values within the above-described range,depending on the type of the first electronic component 101 and thesecond electronic component 111, the method for manufacturing connectionstructure, the method for composite arrangement, and so forth. If theviscosity of the first composite 20′ is lower than 5×10³ cP, uniformdispersibility of the conductive particles 10 in the first composite 20′is degraded, and sedimentation and agglomeration tend to occur. With theviscosity of the first composite 20′ being higher than the viscosity ofthe second composite 30′, the conductive particles 10 mixed into thefirst composite 20′ is inhibited from flowing, and can be efficientlyarranged between the first electrode 110 and the second electrode 114.Therefore, connection reliability between the first electrode 110 andthe second electrode 114 can be ensured.

The first resin 20 and the second resin 30 are formed by curing thefirst composite 20′ and the second composite 30′. The volume shrinkageratio of the first resin 20 due to curing of the first composite 20′ andthe volume shrinkage ratio of the second resin 30 due to curing of thesecond composite 30′ are both preferably equal to or smaller than 4%,and more preferably equal to or smaller than 2%. If the volumeshrinkages ratio of the first resin 20 and the second resin 30 arelarger than 4%, an inner shrinkage stress occurs, warpage due to adifference in flexural rigidity between the first electronic component101 and the second electronic component 111 tends to occur, and physicalconnection reliability between the first electronic component 101 andthe second electronic component 111 is degraded.

The first resin 20 more preferably has high power of adhesion to aconductive material such as a metal material or metal oxide material.The first resin 20 preferably has high power of adhesion to a metalmaterial forming the first electrode 110 and the second electrode 114,and preferably has high power of adhesion to, for example, Au, ITO, andso forth. The second resin 30 preferably has high power of adhesion to aresin material. The second resin 30 preferably has high power ofadhesion to an insulating film material forming the first surface of thefirst member 102 and the second surface of the second member 112, andpreferably has high power of adhesion to an insulating material such as,for example, polyimide, para-based polyamide film, P—SiNx, glass, and soforth. The adhesion power of the first resin 20 is preferably in a rangeequal to or larger than 500 N/m. The adhesion power of the second resin30 is preferably in a range equal to or larger than 700 N/m. Theadhesion power, glass transition temperature, and hardness of each resincan be selected as appropriate, depending on the type of the firstelectronic component 101 and the second electronic component 111, themethod for manufacturing connection structure, and so forth. With thefirst resin 20 and the second resin 30 each being selected depending onthe material of an adherend, the adhesive power between the firstsurface of the first member 102 and the second surface of the secondmember 112 can be further improved. Therefore, physical connectionreliability between the first electronic component 101 and the secondelectronic component 111 can be improved.

The Method for Manufacturing Connection Structure

Next, a method for manufacturing connection structure according to oneembodiment of the present invention is described by using FIG. 2A toFIG. 5E. Since the existing first electronic component 101 and secondelectronic component 111 can be used in the present embodiment, theirdescription is omitted. In FIG. 2A to FIG. 5E, the method of forming theconnection structure 100 is described in detail.

First, the plurality of conductive particles 10 and the first composite20′ are arranged in a predetermined region on the first electrode 110.The plurality of conductive particles 10 and the first composite 20′ aremixed, and are arranged by using an offset printing scheme. Since themixture of the conductive particles 10 and the first composite 20′contains the conductive particles 10, a pad printing scheme oftransferring a printed matter by using a pad is particularly preferable.By using FIG. 2A to FIG. 5E, a method of arranging the plurality ofconductive particles 10 and the first composite 20′ is described.

FIG. 2A to FIG. 2C show a process of arranging the plurality ofconductive particles 10 and the first composite 20′ on a plate 220. FIG.3A to FIG. 3C are sectional views along a C-C′ line of FIG. 2A to FIG.2C. In the present embodiment, the plate 220 is planographic intaglioplate, for example, a waterless planographic plate. The plate 220 hasdepressed parts 226 corresponding to regions where the plurality ofconductive particles 10 and the first composite 20′ are arranged on thefirst surface of the first member 102. The plate 220 includes alyophilic layer 222 and a liquid-repellent layer 224. Theliquid-repellent layer 224 is arranged as a liquid contact surface, andhas an opening. The liquid-repellent layer 224 exposes the lyophiliclayer 222 at a bottom surface of the opening. That is, theliquid-repellent layer 224 having the opening is arranged on an uppersurface of the plate 220, and the lyophilic layer 222 is arranged underthe liquid-repellent layer 224. The depressed parts 226 are formed bythe opening of the liquid-repellent layer 224 and the lyophilic layer222 at the bottom surface of the opening.

The material of the lyophilic layer 222 may be, for example, an aluminumoxide (Al₂O₃). The material of the liquid-repellent layer 224 ispreferably, for example, an elastic silicone resin. The depressed parts226 have a depth substantially equal to the depth of theliquid-repellent layer 224. The depth of the depressed parts 226 isrequired to be larger than the diameter of the conductive particles 10.The plate 220 may be, in addition to a waterless planographic plate, aglass deep-etch plate, a stainless deep-etch plate, a sapphire deep-etchplate, or a zirconia deep-etch plate. The depressed parts 226 whenviewed from the upper surface of the plate 220 are preferably separatedfrom each other by 5 μm or more. If the depressed parts 226 areseparated from each other by less than 5 μm, the liquid-repellent layer224 which separates the adjacent depressed parts 226 tends to be broken,and durability of the plate 220 may be degraded.

In the present embodiment, the shape of each depressed part 226 whenviewed in the opposing direction (D1 direction) of the electrodes iscircle. Also, the depressed part 226 has the same shape in a depthdirection. That is, the depressed part 226 has a shape obtained bycutting out a cylinder from the plate 220. However, the shape of thedepressed part 226 is not limited to this, and the depressed part 226can take any shape with the depth in the above-described range.

In the present embodiment, the mixture of the conductive particles 10and the first composite 20′ is arranged on the plate 220 by using aroller 210. As shown in FIG. 2A to FIG. 2C and FIG. 3A to FIG. 3C, theroller 210 moves as rotating from one end to the other end of the plate220 so that an outer peripheral surface of the roller 210 is in contactwith the upper surface of the plate 220 (upper surface of theliquid-repellent layer 224), thereby arranging the conductive particles10 and the first composite 20′ in the depressed parts 226.

As for the concentration of the conductive particles 10 mixed into thefirst composite 20′, the ratio of the conductive particles 10 to thetotal volume of the conductive particles 10 and the first composite 20′is preferably in a range between a value equal to or larger than 20volume % and a value equal to or smaller than 60 volume %. If the mixingamount of the conductive particles 10 is smaller than 20 volume %, it isdifficult to fill the sufficient number of conductive particles 10 inthe depressed parts 226. If the mixing amount of the conductiveparticles 10 is larger than 60 volume %, operability is degraded, and itis difficult to fill the mixture of the conductive particles 10 and thefirst composite 20′ in the depressed parts 226. By arranging the mixtureof the conductive particles 10 and the first composite 20′ with theroller 210, the conductive particles 10 and the first composite 20′ canbe filled in the depressed parts 226 of the plate 220. Since thedepressed parts 226 have the depth in the above-described range, oneconductive particle 10 can be retained in the depth direction (D1direction) of the depressed parts 226. The number of conductiveparticles 10 arranged in one depressed part 226 is preferably equal toor more than one and equal to or smaller than seven. The number ofconductive particles 10 arranged in one depressed part 226 is preferablyseven and, more preferably three. This arrangement allows the conductiveparticles 10 and the first composite 20′ to be efficiently displaced tothe pad in a process of displacing the mixture of the conductiveparticles 10 and the first composite 20′ to the pad, which will bedescribed further below.

Each depressed part 226 is formed by the opening of the elasticliquid-repellent layer 224. Thus, if the conductive particles 10 makecontact with the liquid-repellent layer 224 as the roller 210 progress,the conductive particles 10 can be retained in the depressed parts 226without damage. Since the depressed parts 226 have the lyophilic layer222 at the bottom, it can retain the first composite 20′. On the otherhand, the liquid-repellent layer 224 arranged on the upper surface ofthe plate 220 makes the first composite 20′ liquid-repellent.

FIG. 4A to FIG. 4C show a process of displacing the mixture of theplurality of conductive particles 10 and the first composite 20′ fromthe plate 220 to a pad 230. As shown in FIG. 4A to FIG. 4C, the pad 230is pressed in a direction substantially perpendicular to the plate 220,and is then pulled away in the direction substantially perpendicular tothe plate 220, thereby displacing the conductive particles 10 and thefirst composite 20′ filled in the depressed parts 226 to the pad 230.Since the viscosity of the first composite 20′ is in a range between avalue equal to or higher than 5×10³ cP and a value equal to or lowerthan 5×10⁵ cP, the conductive particles 10 mixed into the firstcomposite 20′ can be retained on the surface of the pad 230.

The material of the pad 230 is preferably, for example, an elasticsilicone resin or the like. The shape of the pad 230 preferably has atleast a convex configuration. The shape of the pad 230 can be selectedas appropriate depending on the shape of the first electronic component101, the plate 220, and the like.

FIG. 5A and FIG. 5B shows the process of transferring the mixture of theplurality of conductive particles 10 and the first composite 20′ fromthe pad 230 to the first electrode 110. As shown in FIG. 5A and FIG. 5B,the pad 230 is pressed in a direction substantially perpendicular to thefirst electrode 110, and is then pulled away in the directionsubstantially perpendicular to the first electrode 110, therebytransferring the mixture of the conductive particles 10 and the firstcomposite 20′ displaced to the pad 230 onto the first electrode 110. Onthe first surface of the first member 102, the conductive particles 10and the first composite 20′ form a convex configuration in the opposingdirection (D1 direction) of the electrodes. The viscosity of the curableresin material of the first composite 20′ is in the range between avalue equal to or higher than 5×10³ cP and a value equal to or lowerthan 5×10⁵ cP. Thus, the conductive particles 10 mixed into the firstcomposite 20′ can be retained on the first electrode 110. The use ofthis method allows the conductive particles 10 and the first composite20′ to be reliably arranged in a predetermined region on the firstelectrode 110.

Next, the second composite 30′ is arranged on the first surface of thefirst member 102. As shown in FIG. 5C, the second composite 30′ isarranged in a region other than the first electrode 110 on the firstsurface of the first member 102. Furthermore, the second composite 30′is arranged also on the first electrode 110 in a region other than theregion where the plurality of conductive particles 10 and the firstcomposite 20′ are arranged. That is, the second composite 30′ isarranged on the first surface of the first member 102 and in the regionother than the region where the plurality of conductive particles 10 andthe first composite 20′ are arranged. The first composite 20′ and theconductive particles 10 forming a convex configuration on the firstsurface of the first member 102 is buried by the second composite 30′.Although not shown, in the present embodiment, as in the arrangement ofthe mixture of the conductive particles 10 and the first composite 20′,the second composite 30′ is arranged by using a pad printing scheme.However, the method of arranging the second composite 30′ is not limitedto this scheme, and any existing method capable of different coating ina region other than the region where the plurality of conductiveparticles 10 and the first composite 20′ are arranged can be used. Forexample, coating by inkjet or a dispenser, offset printing scheme, orthe like can be used.

The viscosity of the second composite 30′ is in a range between a valueequal to or higher than 2×10³ cP and a value equal to or lower than2×10⁵ cP. It is required that the viscosity of the first composite 20′is twice as high as high as the viscosity of the second composite 30′ orhigher. This allows a flow of the conductive particles 10 mixed into thefirst composite 20′ to be inhibited, and the conductive particles 10 canbe retained on the first electronic component 110.

Next, the second member 112 is mounted on the first surface of the firstmember 102. As shown in FIG. 5D, the first surface of the first member102 and the second surface of the second member 112 are arranged so asto be opposed to each other so that the corresponding plurality of firstelectrodes 110 and plurality of second electrodes 114 are opposed toeach other. The first member 102 and the second member 112 are pressedso that the first surface of the first member 102 and the second surfaceof the second member 112 are pushed in directions substantiallyperpendicular to the respective surfaces. The first surface of the firstmember 102 and the second surface of the second member 112 arepressure-welded to the conductive particles 10, the first composite 20′,and the second composite 30′. Here, the first composite 20′ arranged onthe first electrode 110 has a viscosity higher than that of the secondcomposite 30′, and is thus retained on the first electrode 110 togetherwith the conductive particles 10. The conductive particles 10 and thefirst composite 20′ arranged on the first electrode 110 are arranged soas to be in contact with the second electrode 114, and the secondcomposite 30′ arranged in a region other than the first electrode 110 onthe first surface is arranged so as to be in contact with a region otherthan the second electrode 114 on the second surface.

As shown in FIG. 5E, the first member 102 and the second member 112 arefurther pressed to push the first surface of the first member 102 andthe second surface of the second member 112 in the directionssubstantially perpendicular to the respective surfaces. Here, asufficient pressure is applied to cause the opposing first electrode 110and second electrode 114 to be in contact with upper and lower sides ofone conductive particle 10. The pressure to push the first surface ofthe first member 102 and the second surface of the second member 112 canbe adjusted as appropriate by a repulsive force of the conductiveparticles 10 and elastic forces of the first composite 20′ and thesecond composite 30′.

Here, the conductive particles 10 are pressurized until deformed into anoblate spheroidal shape by receiving pressure from the first electrode110 and the second electrode 114. The pressure deformation amount of theconductive particles 10 is controlled in a range between a value equalto or larger than 10% and a value equal to or smaller than 40% withrespect to a longitudinal diameter of the conductive particles 10 of100%. Here, a stress is applied among the first electrode 110, theconductive particles 10, and the second electrode 114, therebyeliminating the first composite 20′ between the first electrode 110 andthe conductive particles 10 and between the second electrode 114 and theconductive particles 10. Furthermore, even if a natural oxide film isformed on the first electrode 110, the conductive particles 10, or thesecond electrode 114 and its surface is insulated, the first electrode110 and the second electrode 114 are press-welded with the conductiveparticles 10 interposed therebetween, thereby breaking the natural oxidefilm to form a conductive route. Deformation of the conductive particles10 can increase the area of contact between the first electrode 110 andthe conductive particles 10 and the area of contact between the secondelectrode 114 and the conductive particles 10. This arrangement allowsthe conductive particles 10 to electrically connect the first electrode110 and the second electrode 114.

With the first member 102 and the second member 112 pressed, theconnection structure 100 is irradiated with light. The wavelength regionof light is preferably an ultraviolet ray and/or visible ray region. Inparticular, ultraviolet rays are more preferable. The wavelength regionof light can be selected as appropriate depending on the photocuringinitiating component and the like included in the first composite 20′and the second composite 30′. The direction of light irradiation can beselected as appropriate from a first electronic component 101 side or asecond electronic component 111 side, depending on the wavelength regionof light, the materials of the first member 102 and the second member112, and so forth. Also, irradiation of light from both sides ispreferable, and irradiation from a side surface without a shieldingsubstance is also effective. The light irradiation time can be selectedas appropriate depending on the photocuring initiating component, thecurable resin material, and the like contained in the first composite20′ and the second composite 30′. In general, the light irradiation timeis preferably equal to or shorter than approximately three seconds and,more preferable equal to or shorter than one second. In other words,light irradiation intensity, the photocuring initiating component, thecurable resin material, and so forth are selected as appropriate so thatcuring is achieved at room temperatures within the above-described lightirradiation time.

Light irradiation causes most of the first composite 20′ and the secondcomposite 30′ included in the connection structure 100 to be cured atroom temperatures. However, for example, a portion between the firstelectrode 110 and the second electrode 114 which sufficient light doesnot reach may be insufficiently cured. Thus, the material of the firstcomposite 20′ more preferably contains a shielding part curableactivation compound, an anaerobic curing initiating component, or thelike. By containing a shielding part curable activation compound, ananaerobic curing initiating component, or the like, it is possible topromote curing at room temperatures even in a portion which sufficientlight does not reach. By curing the first composite 20′ and the secondcomposite 30′, the first resin 20 and the second resin 30 are formed.This configuration allows physical connection between the first surfaceof the first electronic component 101 and the second surface of thesecond electronic component 111.

According to the present embodiment, a connection structure and a methodfor manufacturing connection structure can be provided that can ensureconductivity between the opposing electrodes with a simple process andcan reduce a short circuit between adjacent connection electrodes, evenif the electrodes arranged on the electronic components have highfineness and high density. Furthermore, since no heat curing connectionscheme is used, the electrodes of the upper and lower substrates havingdifferent coefficients of thermal expansion can be connected with highaccuracy.

Second Embodiment

The configuration of a connection structure according to a secondembodiment is the same as the configuration of the connection structureaccording to the first embodiment. A method for manufacturing connectionstructure according to the present embodiment is the same as the methodfor manufacturing connection structure according to the first embodimentexcept that the process of arranging the mixture of the plurality ofconductive particles 10 and the first composite 20′ and the process ofarranging the second composite 30′ change places. The same descriptionas that of the first embodiment is omitted, and parts different from themethods for manufacturing connection structure according to the firstembodiment are described herein.

The Method for Manufacturing Connection Structure

The method for manufacturing connection structure according to oneembodiment of the present invention is described by using FIG. 6A toFIG. 6F. Since the existing first electronic component 101 and secondelectronic component 111 can be used in the present embodiment, theirdescription is omitted. In FIG. 6A to FIG. 6F, the method of forming theconnection structure 100 is described in detail.

First, the second composite 30′ is arranged on the first surface of thefirst member 102. As shown in FIG. 6A and FIG. 6B, the second composite30′ is arranged in a region other than the first electrode 110 on thefirst surface of the first member 102. Furthermore, the second composite30′ is arranged also on the first electrode 110 in a region other thanthe region where the plurality of conductive particles 10 and the firstcomposite 20′ are arranged, which will be described further below. Thatis, the second composite 30′ is arranged on the first surface of thefirst member 102 and in the region other than the region where theplurality of conductive particles 10 and the first composite 20′ arearranged. On the first surface of the first member 102, the secondcomposite 30′ forms a convex configuration in the opposing direction (D1direction) of the electrodes. Although not shown, in the presentembodiment, the second composite 30′ is arranged by using a pad printingscheme. However, the method of arranging the second composite 30′ is notlimited to this scheme, and any existing method capable of differentcoating in a region other than the region where the plurality ofconductive particles 10 and the first composite 20′ are arranged can beused. For example, coating by inkjet or a dispenser, offset printingscheme, or the like can be used.

The viscosity of the second composite 30′ is in a range between a valueequal to or higher than 2×10³ cP and a value equal to or lower than2×10⁵ cP.

This allows a flow of the second composite 30′ to be inhibited.

Next, the plurality of conductive particles 10 and the first composite20′ are arranged in a predetermined region on the first electrode 110.The plurality of conductive particles 10 and the first composite 20′ aremixed, and are arranged by using an offset printing scheme. Since themixture of the conductive particles 10 and the first composite 20′contains the conductive particles 10, a pad printing scheme oftransferring a printed matter by using a pad is particularly preferable.The region and method for arranging the mixture of the plurality ofconductive particles 10 and the first composite 20′ are the same asthose of the method for manufacturing connection structure according tothe first embodiment, and therefore are not described herein.

FIG. 6C and FIG. 6D shows the process of transferring the mixture of theplurality of conductive particles 10 and the first composite 20′ fromthe pad 230 to the first electrode 110 by the pad printing scheme. Asshown in FIG. 6C and FIG. 6D, the pad 230 is pushed in a directionsubstantially perpendicular to the first electrode 110, and is thenpulled away in the direction substantially perpendicular to the firstelectrode 110, thereby transferring the mixture of the conductiveparticles 10 and the first composite 20′ displaced to the pad 230 ontothe first electrode 110. The second composite 30′ forming a convexconfiguration on the first surface of the first member 102 is buried bythe first composite 20′ and the conductive particles 10. The viscosityof the curable resin material of the first composite 20′ is in the rangebetween a value equal to or higher than 5×10³ cP and a value equal to orlower than 5×10⁵ cP. Thus, the conductive particles 10 mixed into thefirst composite 20′ can be retained on the first electrode 110. The useof this method allows the conductive particles 10 and the firstcomposite 20′ to be reliably arranged in a predetermined region on thefirst electrode 110.

Next, the second electronic component 111 is mounted on the firstsurface of the first electronic component 101. As shown in FIG. 6E, thefirst surface of the first member 102 and the second surface of thesecond member 112 are arranged so as to be opposed to each other so thatthe corresponding plurality of first electrodes 110 and plurality ofsecond electrodes 114 are opposed to each other. The first member 102and the second member 112 are pressed so that the first surface of thefirst member 102 and the second surface of the second member 112 arepushed in directions substantially perpendicular to the respectivesurfaces. The first surface of the first member 102 and the secondsurface of the second member 112 are pressure-welded to the conductiveparticles 10, the first composite 20′, and the second composite 30′.Here, the first composite 20′ arranged on the first electrode 110 has aviscosity higher than that of the second composite 30′, and is thusretained on the first electrode 110 together with the conductiveparticles 10. The conductive particles 10 and the first composite 20′arranged on the first electrode 110 are arranged so as to be in contactwith the second electrode 114, and the second composite 30′ arranged inthe region other than the first electrode 110 on the first surface isarranged so as to be in contact with a region other than the secondelectrode 114 on the second surface.

As shown in FIG. 6F, the first member 102 and the second member 112 arefurther pressed to push the first surface of the first member 102 andthe second surface of the second member 112 in the directionssubstantially perpendicular to the respective surfaces. Here, asufficient pressure is applied to cause the opposing first electrode 110and second electrode 114 to be in contact with upper and lower sides ofone conductive particle 10. The pressure to push the first surface ofthe first member 102 and the second surface of the second member 112 canbe adjusted as appropriate by a repulsive force of the conductiveparticles 10 and elastic forces of the first composite 20′ and thesecond composite 30′. This configuration allows electrical connectionbetween the first electrode 110 and the second electrode 114.

With the first member 102 and the second member 112 pressed, theconnection structure 100 is irradiated with light to cure the firstcomposite 20′ and the second composite 30′. A method of curing the firstcomposite 20′ and the second composite 30′ is the same as that of themethod for manufacturing connection structure according to the firstembodiment, and is therefore not described herein. By curing the firstcomposite 20′ and the second composite 30′, the first resin 20 and thesecond resin 30 are formed. This configuration allows physicalconnection between the first surface of the first electronic component101 and the second surface of the second electronic component 111.

According to the present embodiment, a connection structure and a methodfor manufacturing connection structure can be provided that can ensureconductivity between the opposing electrodes with a simple process andcan reduce a short circuit between adjacent connection electrodes, evenif the electrodes arranged on the electronic component have highfineness and high density. Furthermore, since no heat curing connectionscheme is used, the electrodes of the upper and lower substrates havingdifferent coefficients of thermal expansion can be connected with highaccuracy.

Third Embodiment

The configuration of a connection structure according to a thirdembodiment is the same as the configuration of the connection structureaccording to the first embodiment. A method for manufacturing connectionstructure according to the present embodiment is the same as the methodfor manufacturing connection structure according to the first embodimentexcept that the second composite 30′ is arranged in a region other thanthe second electrode 114 of the second surface. The same description asthat of the first embodiment is omitted, and parts different from themethods for manufacturing connection structure according to the firstembodiment are described herein.

The Method for Manufacturing Connection Structure

The method for manufacturing connection structure according to oneembodiment of the present invention is described by using FIG. 7A toFIG. 7F. Since the existing first electronic component 101 and secondelectronic component 111 can be used in the present embodiment, theirdescription is omitted. In FIG. 7A to FIG. 7F, the method of forming theconnection structure 100 is described in detail.

First, the plurality of conductive particles 10 and the first composite20′ are arranged in a predetermined region on the first electrode 110.The plurality of conductive particles 10 and the first composite 20′ aremixed, and are arranged by using an offset printing scheme. Since themixture of the conductive particles 10 and the first composite 20′contains the conductive particles 10, a pad printing scheme oftransferring a printed matter by using a pad is particularly preferable.The region and method for arranging the mixture of the plurality ofconductive particles 10 and the first composite 20′ are the same asthose of the method for manufacturing connection structure according tothe first embodiment, and therefore are not described herein.

FIG. 7A and FIG. 7B shows the process of transferring the mixture of theplurality of conductive particles 10 and the first composite 20′ fromthe pad 230 to the first electrode 110 by the pad printing scheme. Asshown in FIG. 7A and FIG. 7B, the pad 230 is pushed in a directionsubstantially perpendicular to the first electrode 110, and is thenpulled away in the direction substantially perpendicular to the firstelectrode 110, thereby transferring the mixture of the conductiveparticles 10 and the first composite 20′ displaced to the pad 230 ontothe first electrode 110. On the first surface of the first member 102,the conductive particles 10 and the first composite 20′ form a convexconfiguration in the opposing direction (D1 direction) of theelectrodes. The viscosity of the curable resin material of the firstcomposite 20′ is in the range between a value equal to or higher than5×10³ cP and a value equal to or lower than 5×10⁵ cP. Thus, theconductive particles 10 mixed into the first composite 20′ can beretained on the first electrode 110. The use of this method allows theconductive particles 10 and the first composite 20′ to be reliablyarranged in a predetermined region on the first electrode 110.

Next, the second composite 30′ is arranged on the second surface of thesecond member 112. As shown in FIG. 7C and FIG. 7D, the second composite30′ is arranged in a region other than the second electrode 114 of thesecond surface of the second member 112. Furthermore, the secondcomposite 30′ is arranged also on the second electrode 114 and in aregion other than the region where the plurality of conductive particles10 and the first composite 20′ are arranged, which will be describedfurther below. That is, the second composite 30′ is arranged on thesecond surface of the second member 112 in the region other than theregion where the plurality of conductive particles 10 and the firstcomposite 20′ are arranged. On the second surface of the second member112, the second composite 30′ forms a convex configuration in theopposing direction (D1 direction) of the electrodes. Although not shown,in the present embodiment, the second composite 30′ is arranged by usinga pad printing scheme. However, the method of arranging the secondcomposite 30′ is not limited to this scheme, and any existing methodcapable of different coating in a region other than the region where theplurality of conductive particles 10 and the first composite 20′ arearranged can be used. For example, coating by inkjet or a dispenser,offset printing scheme, or the like can be used.

The viscosity of the second composite 30′ is in a range between a valueequal to or higher than 2×10³ cP and a value equal to or lower than2×10⁵ cP. This allows a flow of the second composite 30′ to beinhibited.

Next, the second electronic component 111 is mounted on the firstsurface of the first electronic component 101. As shown in FIG. 7E, thefirst surface of the first member 102 and the second surface of thesecond member 112 are arranged so as to be opposed to each other so thatthe corresponding plurality of first electrodes 110 and plurality ofsecond electrodes 114 are opposed to each other. The first composite 20′and the conductive particles 10 forming a convex configuration on thefirst surface of the first member 102 is buried by the second composite30′ forming a convex configuration on the second surface of the secondmember 112. The first member 102 and the second member 112 are pressedso that the first surface of the first member 102 and the second surfaceof the second member 112 are pushed in directions substantiallyperpendicular to the respective surfaces. The first surface of the firstmember 102 and the second surface of the second member 112 arepressure-welded to the conductive particles 10, the first composite 20′,and the second composite 30′. Here, the first composite 20′ arranged onthe first electrode 110 has a viscosity higher than that of the secondcomposite 30′, and is thus retained on the first electrode 110 togetherwith the conductive particles 10. The conductive particles 10 and thefirst composite 20′ arranged on the first electrode 110 are arranged soas to be in contact with the second electrode 114, and the secondcomposite 30′ arranged in the region other than the second electrode 114on the second surface is arranged so as to be in contact with a regionother than the first electrode 110 on the first surface.

As shown in FIG. 7F, the first member 102 and the second member 112 arefurther pressed to push the first surface of the first member 102 andthe second surface of the second member 112 in the directionssubstantially perpendicular to the respective surfaces. Here, asufficient pressure is applied to cause the opposing first electrode 110and second electrode 114 to be in contact with upper and lower sides ofone conductive particle 10. The pressure to push the first surface ofthe first member 102 and the second surface of the second member 112 canbe adjusted as appropriate by a repulsive force of the conductiveparticles 10 and elastic forces of the first composite 20′ and thesecond composite 30′. This configuration allows electrical connectionbetween the first electrode 110 and the second electrode 114.

With the first member 102 and the second member 112 pressed, theconnection structure 100 is irradiated with light to cure the firstcomposite 20′ and the second composite 30′. A method of curing the firstcomposite 20′ and the second composite 30′ is the same as that of themethod for manufacturing connection structure according to the firstembodiment, and is therefore not described herein. By curing the firstcomposite 20′ and the second composite 30′, the first resin 20 and thesecond resin 30 are formed. This configuration allows physicalconnection between the first surface of the first electronic component101 and the second surface of the second electronic component 111.

According to the present embodiment, a connection structure and a methodfor manufacturing connection structure can be provided that can ensureconductivity between the opposing electrodes with a simple process andcan reduce a short circuit between adjacent connection electrodes, evenif the electrodes arranged on the electronic component have highfineness and high density. Furthermore, since no heat curing connectionscheme is used, the electrodes of the upper and lower substrates havingdifferent coefficients of thermal expansion can be connected with highaccuracy.

Fourth Embodiment

The configuration of a connection structure according to a fourthembodiment is the same as the configuration of the connection structureaccording to the first embodiment. A method for manufacturing connectionstructure according to the present embodiment is the same as the methodfor manufacturing connection structure according to the first embodimentexcept that the second composite 30′ is arranged in a region other thanthe first electrode 110 of the first member 102 and the plurality ofconductive particles 10 and the first composite 20′ are arranged on thesecond electrode 114 of the second member 112. The same description asthat of the first embodiment is omitted, and parts different from themethod for manufacturing connection structures according to the firstembodiment are described herein.

The Method for Manufacturing Connection Structure

The method for manufacturing connection structure according to oneembodiment of the present invention is described by using FIG. 8A toFIG. 8F. Since the existing first electronic component 101 and secondelectronic component 111 can be used in the present embodiment, theirdescription is omitted. In FIG. 8A to FIG. 8F, the method of forming theconnection structure 100 is described in detail.

First, the second composite 30′ is arranged on the first surface of thefirst member 102. As shown in FIG. 8A and FIG. 8B, the second composite30′ is arranged in a region other than the first electrode 110 on thefirst surface of the first member 102. Furthermore, the second composite30′ is arranged also on the first electrode 110 in a region other thanthe region where the plurality of conductive particles 10 and the firstcomposite 20′ are arranged, which will be described further below. Thatis, the second composite 30′ is arranged on the first surface of thefirst member 102 and in the region other than the region where theplurality of conductive particles 10 and the first composite 20′ arearranged. On the first surface of the first member 102, the secondcomposite 30′ forms a convex configuration in the opposing direction (D1direction) of the electrodes. Although not shown, in the presentembodiment, the second composite 30′ is arranged by using a pad printingscheme. However, the method of arranging the second composite 30′ is notlimited to this scheme, and any existing method capable of differentcoating in a region other than the region where the plurality ofconductive particles 10 and the first composite 20′ are arranged can beused. For example, coating by inkjet or a dispenser, offset printingscheme, or the like can be used.

The viscosity of the second composite 30′ is in a range between a valueequal to or higher than 2×10³ cP and a value equal to or lower than2×10⁵ cP. This allows a flow of the second composite 30′ to beinhibited.

Next, the plurality of conductive particles 10 and the first composite20′ are arranged in a predetermined region on the second electrode 114.The plurality of conductive particles 10 and the first composite 20′ aremixed, and are arranged by using an offset printing scheme. Since themixture of the conductive particles 10 and the first composite 20′contains the conductive particles 10, a pad printing scheme oftransferring a printed matter by using a pad is particularly preferable.The region and method for arranging the mixture of the plurality ofconductive particles 10 and the first composite 20′ are the same asthose of the method for manufacturing connection structure according tothe first embodiment, and therefore are not described herein.

FIG. 8C and FIG. 8D shows the process of transferring the mixture of theplurality of conductive particles 10 and the first composite 20′ fromthe pad 230 to the second electrode 114 by the pad printing scheme. Asshown in FIG. 8C and FIG. 8D, the pad 230 is pushed in a directionsubstantially perpendicular to the second electrode 114, and is thenpulled away in the direction substantially perpendicular to the secondelectrode 114, thereby transferring the mixture of the conductiveparticles 10 and the first composite 20′ displaced to the pad 230 ontothe second electrode 114. On the second surface of the second member112, the conductive particles 10 and the first composite 20′ form aconvex configuration in the opposing direction (D1 direction) of theelectrodes. The viscosity of the curable resin material of the firstcomposite 20′ is in the range between a value equal to or higher than5×10³ cP and a value equal to or lower than 5×10⁵ cP. Thus, theconductive particles 10 mixed into the first composite 20′ can beretained on the second electrode 114. The use of this method allows theconductive particles 10 and the first composite 20′ to be reliablyarranged in a predetermined region on the second electrode 114.

Next, the second electronic component 111 is mounted on the firstsurface of the first electronic component 101. As shown in FIG. 8E, thefirst surface of the first member 102 and the second surface of thesecond member 112 are arranged so as to be opposed to each other so thatthe corresponding plurality of first electrodes 110 and plurality ofsecond electrodes 114 are opposed to each other. The second composite30′ forming a convex configuration on the first surface of the firstmember 102 is buried by the first composite 20′ and the conductiveparticles 10 forming a convex configuration on the second surface of thesecond member 112. The first member 102 and the second member 112 arepressed so that the first surface of the first member 102 and the secondsurface of the second member 112 are pushed in directions substantiallyperpendicular to the respective surfaces. The first surface of the firstmember 102 and the second surface of the second member 112 arepressure-welded to the conductive particles 10, the first composite 20′,and the second composite 30′. Here, the first composite 20′ arranged onthe first electrode 110 has a viscosity higher than that of the secondcomposite 30′, and is thus retained on the first electrode 110 togetherwith the conductive particles 10. The conductive particles 10 and thefirst composite 20′ arranged on the second electrode 114 are arranged soas to be in contact with the first electrode 110, and the secondcomposite 30′ arranged in the region other than the first electrode 110of the first surface is arranged so as to be in contact with a regionother than the second electrode 114 on the second surface.

As shown in FIG. 8F, the first member 102 and the second member 112 arefurther pressed to push the first surface of the first member 102 andthe second surface of the second member 112 in the directionssubstantially perpendicular to the respective surfaces. Here, asufficient pressure is applied to cause the opposing first electrode 110and second electrode 114 to be in contact with upper and lower sides ofone conductive particle 10. The pressure to push the first surface ofthe first member 102 and the second surface of the second member 112 canbe adjusted as appropriate by a repulsive force of the conductiveparticles 10 and elastic forces of the first composite 20′ and thesecond composite 30′. This configuration allows electrical connectionbetween the first electrode 110 and the second electrode 114.

With the first member 102 and the second member 112 pressed, theconnection structure 100 is irradiated with light to cure the firstcomposite 20′ and the second composite 30′. A method of curing the firstcomposite 20′ and the second composite 30′ is the same as that of themethod for manufacturing connection structure according to the firstembodiment, and is therefore not described herein. By curing the firstcomposite 20′ and the second composite 30′, the first resin 20 and thesecond resin 30 are formed. This configuration allows physicalconnection between the first surface of the first electronic component101 and the second surface of the second electronic component 111.

According to the present embodiment, a connection structure and a methodfor manufacturing connection structure can be provided that can ensureconductivity between the opposing electrodes with a simple process andcan reduce a short circuit between adjacent connection electrodes, evenif the electrodes arranged on the electronic component have highfineness and high density. Furthermore, since no heat curing connectionscheme is used, the electrodes of the upper and lower substrates havingdifferent coefficients of thermal expansion can be connected with highaccuracy.

Fifth Embodiment

The configuration of a connection structure according to a fifthembodiment is the same as the configuration of the connection structureaccording to the first embodiment except that insulating particles 40are contained in the region where the second resin 30 is arranged. Thesame description as that of the first embodiment is omitted, and partsdifferent from the connection structure according to the firstembodiment are described herein.

Configuration of Connection Structure

FIG. 9A to FIG. 9C shows the configuration of a connection structureaccording to one embodiment of the present invention. FIG. 9A is a planview of the connection structure according to one embodiment of thepresent invention. FIG. 9B is a sectional view along a D-D′ line of FIG.9A. FIG. 9C is an enlarged sectional view of a conductive particle in aregion E of FIG. 9B.

As shown in FIG. 9A and FIG. 9B, a connection structure 100 a accordingto the present embodiment includes the first member 102 having the firstsurface, the first electrode 110, the second member 112 having thesecond surface, the second electrode 114, the conductive particles 10,the first resin 20, the second resin 30, and insulating particles 40.

The second resin 30 and the plurality of insulating particles 40 arearranged between the first surface of the first member 102 and thesecond surface of the second member 112. The second resin 30 and theplurality of insulating particles 40 are arranged in a region notbetween the opposing first electrode 110 and second electrode 114. Thesecond resin 30 and the plurality of insulating particles 40 arearranged between a region other than the first electrode of the firstsurface and a region other than the second electrode of the secondsurface. That is, the second resin 30 and the plurality of insulatingparticles 40 are arranged between the plurality of first electrodes 110adjacent in the surface direction (D2-D3 surface direction) and on theperiphery thereof (between the plurality of second electrodes 114adjacent in the surface direction and on the periphery thereof).Furthermore, the second resin 30 and the insulating particles 40 arealso arranged between the first electrode 110 and the second electrode114 and in a region other than the region where the conductive particles10 and the first resin 20 are arranged. The second resin 30 and theinsulating particles 40 are arranged between the regions adjacent in thesurface direction (D2-D3 surface direction) where the plurality ofconductive particles 10 and the first resin 20 are arranged and on theperiphery thereof. The plurality of insulating particles 40 aredispersed in the second resin 30. When viewed in the opposing direction(D1 direction) of the electrodes, the plurality of respective conductiveparticles 10 are surrounded by the first resin 20, and the respectiveinsulating particles 40 are surrounded by the second resin 30.Furthermore, the conductive particles 10 and the first resin 20 aresurrounded by the second resin 30 and the insulating particles 40 in thesurface direction (D2-D3 surface direction).

The plurality of insulating particles 40 are arranged in the surfacedirection (D2-D3 surface direction) between the opposing first surfaceand second surface in a region other than the region where theconductive particles 10 and the first resin 20 are arranged. Oneinsulating particle 40 is arranged between the opposing first surfaceand second surface in the opposing direction (D1 direction) of the firstsurface and the second surface in a region other than the region wherethe conductive particles 10 and the first resin 20 are arranged. Therespective insulating particles 40 may be in contact with the opposingfirst surface and second surface. The insulating particles 40 may bepressured and deformed in the opposing direction (D1 direction) of theelectrodes between the first surface and the second surface. With astress provided among the first surface, the insulating particles 40,and the second surface, a stress among the first electrode 110, theconductive particles 10, and the second electrode 114 can be dispersed,and reliability of the connection structure 100 a is further improved.

The insulating particle 40 included in the connection structure 100 amay have a spherical shape. The diameter (longitudinal diameter) of theinsulating particle 40 when viewed in the opposing direction (D1direction) of the electrodes is in a range between a value equal to orlarger than 0.1 μm and a value equal to or smaller than 10 μm. Thematerial of the insulating particle 40 is not limited to particularmaterials, and any can be selected as appropriate for use from amongknown insulating particles. The diameter (longitudinal diameter) of theinsulating particle 40 can be selected as appropriate from values in theabove-described range, depending on the size of the conductive particle10, the materials and viscosities of the first composite 20′ and thesecond composite 30′, the method for manufacturing connection structure,and so forth.

While the insulating particle 40 included in the connection structure100 a has a spherical shape in FIG. 9A and FIG. 9B, the insulatingparticle 40 may have, for example, a fiber shape. As the material of theinsulating particle 40, cellulose nanofiber can also be used. The use ofthese insulating particles 40 increases the strength and stiffness withrespect to exfoliation, and improves physical connection reliabilitybetween the first electronic component 101 and the second electroniccomponent 111.

As for the concentration of the insulating particles 40 arranged betweenthe opposing first surface and second surface in the region other thanthe region where the conductive particles 10 and the first resin 20 arearranged when viewed in the opposing direction (D1 direction) of theelectrodes is preferably in a range between a value equal to or largerthan 10 volume % and a value equal to or smaller than 50 volume % withrespect to a total volume of the insulating particles 40 and the secondcomposite 30′. This arrangement can prevent a short circuit between theplurality of first electrodes 110 adjacent in the surface direction(D2-D3 surface direction), between the plurality of second electrodes114 adjacent in the surface direction (D2-D3 surface direction), andbetween the first electrode 110 and the second electrode 114 not opposedto each other. Also, a flow of the conductive particles 10 mixed intothe first composite 20′ is inhibited, and the conductive particles 10can be efficiently arranged between the first electrode 110 and thesecond electrode 114. Therefore, insulation reliability and connectionreliability of the connection structure 100 a can be ensured.

The Method for Manufacturing Connection Structure

A method for manufacturing connection structure according to oneembodiment of the present invention is the same as the method formanufacturing connection structure according to the first embodimentexcept that a mixture of the plurality of insulating particles 40 andthe second composite 30′ is arranged in place of the second composite30′. The same description as that of the first embodiment is omitted,and parts different from the methods for manufacturing connectionstructure according to the first embodiment are described herein. Also,the present embodiment is not limited to this, and can be applied to thesecond to fourth embodiments.

The plurality of insulating particles 40 and the second composite 30′are mixed, and are arranged by using an offset printing scheme. Sincethe mixture of the insulating particles 40 and the second composite 30′contains the insulating particles 40, a pad printing scheme oftransferring a printed matter by using a pad is particularly preferable.

As for the concentration of the insulating particles 40 mixed into thesecond composite 30′, the insulating particles 40 is preferably in arange between a value equal to or larger than 10 volume % and a valueequal to or smaller than 50 volume % with respect to a total volume ofthe insulating particles 40 and the second composite 30′. If the mixingamount of the insulating particles 40 is smaller than 10 volume %, it isdifficult to arrange a sufficient number of insulating particles 40. Ifthe mixing amount of the insulating particles 40 is larger than 50volume %, operability is degraded, and it is difficult to arrange themixture of the insulating particles 40 and the second composite 30′. Amethod of arranging the mixture of the plurality of insulating particles40 and the second composite 30′ is the same as the method of arrangingthe mixture of the plurality of conductive particles 10 and the firstcomposite 20′, and is thus omitted herein.

According to the present embodiment, a connection structure and itsmethod for manufacturing can be provided capable of ensuringconductivity between the opposing electrodes with a simple process andreducing a short circuit between adjacent connection electrodes, even ifthe electrodes arranged on the electronic component have high finenessand high density.

Sixth Embodiment

The configuration of a connection structure according to a sixthembodiment is the same as the configuration of the connection structureaccording to the first embodiment except that the conductivenanoparticles 50 are further contained in the region where the firstresin 20 is arranged. The same description as that of the firstembodiment is omitted, and parts different from the connection structureaccording to the first embodiment are described herein.

Configuration of Connection Structure

FIG. 10A to FIG. 10C shows the configuration of a connection structureaccording to one embodiment of the present invention. FIG. 10A is a planview of the connection structure according to one embodiment of thepresent invention. FIG. 10B is a sectional view along an F-F′ line ofFIG. 10A. FIG. 10C is an enlarged sectional view of a conductiveparticle in a region G of FIG. 10B.

As shown in FIG. 10A and FIG. 10B, a connection structure 100 baccording to the present embodiment includes the first member 102 havingthe first surface, the first electrode 110, the second member 112 havingthe second surface, the second electrode 114, the conductive particles10, the first resin 20, the second resin 30, and conductivenanoparticles 50.

The plurality of conductive particles 10, the plurality of conductivenanoparticles 50 and the first resin 20 are arranged between theopposing first electrode 110 and second electrode 114. The plurality ofconductive particles 10 and the plurality of conductive nanoparticles 50are arranged between the opposing first electrode 110 and secondelectrode 114 in the surface direction (D2-D3 surface direction). Oneconductive particle 10 and the plurality of conductive nanoparticles 50are arranged between the opposing first electrode 110 and secondelectrode 114 in the opposing direction (D1 direction) of theelectrodes. The respective conductive particles 10 may be in contactwith the plurality of conductive nanoparticles 50 and the opposing firstelectrode 110 and second electrode 114. As shown in FIG. 10C, by themethod for manufacturing connection structure, the conductive particles10 is pressured and deformed between the first electrode 110 and thesecond electrode 114 in the opposing direction (D1 direction) of theelectrodes. Here, the plurality of conductive nanoparticles 50 may bearranged between the conductive particles 10 and the first electrode 110or between the conductive particles 10 and the second electrode 114. Adistance between the first electrode 110 and the second electrode 114 inthe opposing direction (D1 direction) of the electrodes is substantiallyequal to the height of the conductive particle 10 in the opposingdirection (D1 direction) of the electrodes. The plurality of conductivenanoparticles 50 may be arranged at a contact part between the firstelectrode 110 and the conductive particle 10 and a contact part betweenthe second electrode 114 and the conductive particle 10 when a stress isapplied among the first electrode 110, the conductive particles 10, andthe second electrode 114. Even if a natural oxide film is formed on thefirst electrode 110, the conductive particles 10, or the secondelectrode 114 and its surface is insulated, the conductive nanoparticles50 are arranged when the first electrode 110 and the second electrode114 are pressure-welded with the conductive particle 10 interposedtherebetween, thereby breaking the film to form a conductive route.Furthermore, with the plurality of conductive nanoparticles 50 arranged,the area of contact region between the first electrode 110 and theconductive particle 10 and the area of contact region between the secondelectrode 114 and the conductive particle 10 can be increased. With theplurality of conductive nanoparticles 50 arranged in this manner, theconductive particles 10 can further reliably connect the first electrode110 and the second electrode 114, and connection reliability of theconnection structure 100 b can be improved.

The plurality of conductive particles 10 and the plurality of conductivenanoparticles 50 are dispersed in the first resin 20 between the firstelectrode 110 and the second electrode 114. The respective conductivenanoparticles 50 and conductive particles 10 are surrounded by the firstresin 20 between the first electrode 110 and the second electrode 114.The first resin 20 is an insulating resin. Thus, the connectionstructure 100 b has insulation properties in the surface direction(D2-D3 surface direction). However, the plurality of conductiveparticles 10 and the plurality of conductive nanoparticles 50 arrangedbetween the opposing first electrode 110 and second electrode 114 andadjacent in the surface direction (D2-D3 surface direction) may be incontact with each other. When the conductive particles 10 and theplurality of conductive nanoparticles 50 adjacent in the surfacedirection (D2-D3 surface direction) are in contact with each other,electrical connection of adjacent conductive particles 10 can beimproved. This arrangement allows the conductive particles 10 and theconductive nanoparticles 50 to further reliably connect the opposingfirst electrode 110 and second electrode 114 electrically.

The conductive nanoparticle 50 included in the connection structure 100b may have a spherical shape. The diameter of the conductivenanoparticle 50 may be in a range between a value equal to or largerthan 10⁻³ μm and a value equal to or smaller than 10⁻¹ μm. As a materialof the conductive nanoparticles 50, any can be selected as appropriatefrom among known conductive particles for use. As the material of theconductive nanoparticles 50, Ni-based nanoparticles less prone tooxidation and with less migration are preferable, but the material maybe Cu-based nanoparticles. The material may be nanoparticles in a coreand shell configuration formed of a Cu-based metal as a core and aNi-based metal as a shell. The diameter and material of the conductivenanoparticle 50 can be selected as appropriate from values in theabove-described range, depending on the size and material of theconductive particle 10, the materials and viscosities of the firstcomposite 20′ and the second composite 30′, the method for manufacturingconnection structure, and so forth.

The Method for Manufacturing Connection Structure

A method for manufacturing connection structure according to oneembodiment of the present invention is the same as the method formanufacturing connection structure according to the first embodimentexcept that a mixture of the plurality of conductive particles 10, theplurality of conductive nanoparticles 50, and the first composite 20′ isarranged in place of the plurality of conductive particles 10 and thefirst composite 20′. The same description as that of the firstembodiment is omitted, and parts different from the methods formanufacturing connection structure according to the first embodiment aredescribed herein. Also, the present embodiment is not limited to this,and can be applied to the second to fourth embodiments.

The plurality of conductive particles 10, the plurality of conductivenanoparticles 50, and the first composite 20′ are mixed, and arearranged by using an offset printing scheme. Since the mixture of theplurality of conductive particles 10, the plurality of conductivenanoparticles 50, and the first composite 20′ contains the conductiveparticles 10, a pad printing scheme of transferring a printed matter byusing a pad is particularly preferable.

As for the concentration of the conductive nanoparticles 50 mixed intothe first composite 20′, the conductive nanoparticles 50 is preferablyin a range between a value equal to or larger than 0.1 weight % and avalue equal to or smaller than 10 weight % with respect to a totalvolume of the plurality of conductive particles 10, the plurality ofconductive nanoparticles 50, and the first composite 20′. If the mixingamount of the conductive nanoparticles 50 is smaller than 0.1 weight %,it is difficult to arrange a sufficient number of conductivenanoparticles 50. If the mixing amount of the conductive nanoparticles50 is larger than 10 weight %, operability is degraded, and it isdifficult to arrange the mixture of the plurality of conductiveparticles 10, the plurality of conductive nanoparticles 50, and thefirst composite 20′. A method of arranging the mixture of the pluralityof conductive particles 10, the plurality of conductive nanoparticles50, and the first composite 20′ is the same as the method of arrangingthe mixture of the plurality of conductive particles 10 and the firstcomposite 20′, and is thus omitted herein.

According to the present embodiment, a connection structure and a methodfor manufacturing connection structure can be provided that can ensureconductivity between the opposing electrodes with a simple process andcan reduce a short circuit between adjacent connection electrodes, evenif the electrodes arranged on the electronic component have highfineness and high density.

The present invention is not limited to the above-described embodiments,and can be modified as appropriate in a range not deviating from thegist of the invention. Also, the embodiments can be combined asappropriate.

First Example

FIG. 11A and FIG. 11B show an example of a connection structureaccording to one example of the present invention. FIG. 11A is a diagramof an arrangement pattern of the conductive particles 10 and the firstresin 20 of a connection structure according to a first example of thepresent invention. FIG. 11B is a diagram of an arrangement pattern ofthe first resin 20 and the second resin 30 of the connection structureaccording to the first example of the present invention. Parameters ofthe connection structure of the first example are as follows.

-   -   Width (short side) (A1) of the first electrode 110=12 μm    -   Distance (B1) between the first electrodes 110=9 μm    -   Pitch (A1+B1=C1) of the first electrode 110=21 μm    -   Length (long side) (D1) of the first electrode 110=84 μm    -   Area (A1×D1) of the first electrode 110=1008 μm²    -   Area of one region where the conductive particles 10 and the        first resin 20 are arranged=64 μm²    -   Total area of regions where the conductive particles 10 and the        first resin 20 are arranged per electrode=448 μm²    -   Number of regions where the conductive particles 10 and the        first resin 20 are arranged per electrode=7    -   Number of conductive particles 10 arranged per region where the        conductive particles 10 and the first resin 20 are arranged=3    -   Number of conductive particles 10 arranged per electrode=21

Second Example

FIG. 12A and FIG. 12B show an example of a connection structureaccording to one example of the present invention. FIG. 12A is a diagramof an arrangement pattern of the conductive particles 10 and the firstresin 20 of a connection structure according to a second example of thepresent invention. FIG. 12B is a diagram of an arrangement pattern ofthe first resin 20 and the second resin 30 of the connection structureaccording to the second example of the present invention. Parameters ofthe connection structure of the second example are as follows.

-   -   Width (short side) (A2) of the first electrode 110=9 μm    -   Distance (B2) between the first electrodes 110=6 μm    -   Pitch (A2+B2=C2) of the first electrode 110=15 μm    -   Length (long side) (D2) of the first electrode 110=78 μm    -   Area (A2×D2) of the first electrode 110=702 μm²    -   Area of one region where the conductive particles 10 and the        first resin 20 are arranged=40 μm²    -   Total area of regions where the conductive particles 10 and the        first resin 20 are arranged per electrode=280 μm²    -   Number of regions where the conductive particles 10 and the        first resin 20 are arranged per electrode=7    -   Number of conductive particles 10 arranged per region where the        conductive particles 10 and the first resin 20 are arranged=2    -   Number of conductive particles 10 arranged per electrode=14

Third Example

FIG. 13A and FIG. 13B show an example of a connection structureaccording to one example of the present invention. FIG. 13A is a diagramof an arrangement pattern of the conductive particles 10 and the firstresin 20 of a connection structure according to a third example of thepresent invention. FIG. 13B is a diagram of an arrangement pattern ofthe first resin 20 and the second resin 30 of the connection structureaccording to the third example of the present invention. Parameters ofthe connection structure of the third example are as follows.

-   -   Width (short side) (A3) of the first electrode 110=12 μm    -   Distance (B3) between the first electrodes 110=9 μm    -   Pitch (A3+B3=C3) of the first electrode 110=21 μm    -   Length (long side) (D3) of the first electrode 110=105 μm    -   Area (A3×D3) of the first electrode 110=1260 μm²    -   Area of one region where the conductive particles 10 and the        first resin 20 are arranged=113 μm²    -   Total area of regions where the conductive particles 10 and the        first resin 20 are arranged per electrode=791 μm²    -   Number of regions where the conductive particles 10 and the        first resin 20 are arranged per electrode=7    -   Number of conductive particles 10 arranged per region where the        conductive particles 10 and the first resin 20 are arranged=7    -   Number of conductive particles 10 arranged per electrode=49

Fourth Example

FIG. 14A and FIG. 14B show an example of a connection structureaccording to one example of the present invention. FIG. 14A is a diagramof an arrangement pattern of the conductive particles 10 and the firstresin 20 of a connection structure according to a fourth example of thepresent invention. FIG. 14B is a diagram of an arrangement pattern ofthe first resin 20 and the second resin 30 of the connection structureaccording to the fourth example of the present invention. Parameters ofthe connection structure of the fourth example are as follows.

-   -   Width (short side) (A4) of the first electrode 110=9 μm    -   Distance (B4) between the first electrodes 110=6 μm    -   Pitch (A4+B4=C4) of the first electrode 110=15 μm    -   Length (long side) (D4) of the first electrode 110=84 μm    -   Area (A4×D4) of the first electrode 110=756 μm²    -   Area of one region where the conductive particles 10 and the        first resin 20 are arranged=64 μm²    -   Total area of regions where the conductive particles 10 and the        first resin 20 are arranged per electrode=448 μm²    -   Number of regions where the conductive particles 10 and the        first resin 20 are arranged per electrode=7    -   Number of conductive particles 10 arranged per region where the        conductive particles 10 and the first resin 20 are arranged=3    -   Number of conductive particles 10 arranged per first electrode        110=21

Fifth Example

FIG. 15A and FIG. 15B show an example of a connection structureaccording to one example of the present invention. FIG. 15A is a diagramof an arrangement pattern of the conductive particles 10 and the firstresin 20 of a connection structure according to a fifth example of thepresent invention. FIG. 15B is a diagram of an arrangement pattern ofthe first resin 20 and the second resin 30 of the connection structureaccording to the fifth example of the present invention. Parameters ofthe connection structure of the fifth example are as follows.

-   -   Width (short side) (A5) of the first electrode 110=21 μm    -   Distance (B5) between the first electrodes 110=10 μm    -   Pitch (A5+B5=C5) of the first electrode 110=31 μm    -   Length (long side) (D5) of the first electrode 110=21 μm    -   Area (A5×D5) of the first electrode 110=441 μm²    -   Area of region a where the conductive particles 10 and the first        resin 20 are arranged=64 μm²    -   Total area of region a where the conductive particles 10 and the        first resin 20 are arranged per electrode=128 μm²    -   Number of region a where the conductive particles 10 and the        first resin 20 are arranged per electrode=2    -   Number of conductive particles 10 arranged per region a where        the conductive particles 10 and the first resin 20 are        arranged=3    -   Area of region 13 where the conductive particles 10 and the        first resin 20 are arranged=40 μm²    -   Total area of region 13 where the conductive particles 10 and        the first resin 20 are arranged per electrode=80 μm²    -   Number of region 13 where the conductive particles 10 and the        first resin 20 are arranged per electrode=2    -   Number of conductive particles 10 arranged per region 13 where        the conductive particles 10 and the first resin 20 are        arranged=2    -   Number of conductive particles 10 arranged per electrode=10

Sixth Example

FIG. 16A and FIG. 16B show an example of a connection structureaccording to one example of the present invention. FIG. 16A is a diagramof an arrangement pattern of the conductive particles 10 and the firstresin 20 of a connection structure according to a sixth example of thepresent invention. FIG. 16B is a diagram of an arrangement pattern ofthe first resin 20 and the second resin 30 of the connection structureaccording to the sixth example of the present invention. Parameters ofthe connection structure of the sixth example are as follows.

-   -   Width (short side) (A6) of the first electrode 110=15 μm    -   Distance (B6) between the first electrodes 110=10 μm    -   Pitch (A6+B6=C6) of the first electrode 110=25 μm    -   Length (long side) (D6) of the first electrode 110=30 μm    -   Area (A6×D6) of the first electrode 110=450 μm²    -   Area of the region where the conductive particles 10 and the        first resin 20 are arranged=113 μm²    -   Total area of regions where the conductive particles 10 and the        first resin 20 are arranged per electrode=226 μm²    -   Number of regions where the conductive particles 10 and the        first resin 20 are arranged=2    -   Number of conductive particles 10 arranged per region=7    -   Number of conductive particles 10 arranged per electrode=14

As shown in the first to sixth examples, according to one embodiment ofthe present invention, even if the electrodes arranged on the electroniccomponents have high fineness and high density, conductivity betweenopposing electrodes is ensured with simple process, and a short circuitbetween adjacent electrodes can be reduced.

What is claimed is:
 1. A connection structure comprising: a first memberhaving a first surface; a plurality of first electrodes located on thefirst surface; a second member having a second surface opposed to thefirst surface; a plurality of second electrodes opposed to the aplurality of first electrodes and located on the second surface; a firstresin and conductive particles arranged between the at least one of theplurality of first electrodes and at least one of the plurality ofsecond electrodes, the conductive particles including a particle corehaving elasticity coated with metals; and a second resin arrangedbetween a first region surrounding the at least one of the plurality offirst electrodes on the first surface and a second region surroundingthe at least one of the plurality of second electrodes on the secondsurface, an insulating film arranged in the first region, wherein thesecond resin is in contact with the insulating film in the first regionand the second surface in the second region, and the first resin and thesecond resin have different compositions from each other, wherein theconductive particles are arranged between the at least one of theplurality of first electrodes and the at least one of the plurality ofsecond electrodes in a range of seven per 400 μm² or more and twenty per400 μm² or less.
 2. The connection structure according to claim 1,wherein the first resin is in contact with the at least one of theplurality of first electrodes and the at least one of the plurality ofsecond electrodes.
 3. The connection structure according to claim 1,wherein the second composite contains a dendrimer or hyperbranch polymerstructure portion having an acryl group.
 4. The connection structureaccording to claim 1, wherein the second composite contains anene/thiol-based curable resin containing an ethylene unsaturatedcompound and a thiol compound, and a curable component of at least oneof the ethylene unsaturated compound and the thiol compound is a9,9-bisarylfluorene compound.
 5. The connection structure according toclaim 1, wherein the conductive particles are arranged only between theplurality of first electrodes and the plurality of second electrodes. 6.The connection structure according to claim 1, wherein at least one ofthe conductive particles is in contact with the at least one of theplurality of first electrodes and the at least one of the plurality ofsecond electrodes.
 7. The connection structure according to claim 6,wherein at least one of the conductive particles is deformed bycompression of the at least one of the plurality of first electrodes andthe at least one of the plurality of second electrodes.
 8. Theconnection structure according to claim 1, wherein the first resincontains conductive nanoparticles.
 9. The connection structure accordingto claim 1, wherein the second resin contains insulating particles.